Merkel has invited 85 guests, including representatives of immigrant groups, national and regional officials, to a so-called "integration summit" at the chancellery.
The summit is meant to kick off a yearlong effort to draw up an "integration plan."
The government estimates that 15 million people living in Germany, which has a total population of 82 million, have an immigrant background of some description - with origins outside the country or as ethnic Germans from the former Soviet Union.
Its main cause for concern is "clear integration deficits" among second- and third-generation immigrants - among them poor German language skills, high unemployment and "lacking acceptance of basic rules" of society, including women's rights.
Germany has escaped immigrant riots such as those that wracked Paris suburbs last year and saw only limited protests this year over caricatures of the Prophet Mohammed. However, worries persist that more needs to be done to integrate large communities of Turks and others, according to the AP.
A law that took effect last year made government-funded German language and civics courses obligatory for newly arrived foreign residents.